Transient visual loss following endoscopic third ventriculostomy in a child with a posterior fossa tumour: consideration of intracranial pressure control

Abstract

Visual loss following intracranial pressure (ICP) reduction in patients with a brain tumour, termed post-decompression optic neuropathy (PDON), is rare but typically results in permanent visual impairment. We report the case of a 15-year-old boy with medulloblastoma who presented with obstructive hydrocephalus and severe papilloedema (Frisén grade V). He experienced rapid visual deterioration after initial management with endoscopic third ventriculostomy and external ventricular drainage (EVD), despite maintaining controlled ICP levels (EVD height set at 30 cmH₂O). Remarkably, his vision gradually improved over five months, recovering from bare light perception to 0.20 (20/100) in both eyes. Previous studies suggest that a rapid reduction in ICP can impair optic nerve head perfusion, potentially causing ischaemic injury. This case suggests the potential risk associated with ICP management in patients with brain tumour and severe papilloedema. Because the visual outcomes of PDON can be devastating, careful ICP management and close ophthalmologic monitoring are crucial.

Keywords: Brain tumour; Hydrocephalus; Intracranial pressure; Optic neuropathy; Paediatric; Papilloedema.